Question

A rectangular channel of width 3m carries a discharge of 10 cumecs. What will be the section factor at the critical state?

• A. 3.18
• B. 2.6
• C. None of these
• D. 1.0

Answer 1

The correct option is A 3.18

Given, Q=10 cumecs, B=3 m

Critical depth of flow, $y_c=(\frac{q^2}{g}{)}^{\frac{1}{3}}$

=$(\frac{\frac{10}{3}}{9.81}{)}^{\frac{1}{3}}$

=1.04 m

$Atcriticalstate,Areaofflow,A_c=B{y}_c$

$=3\times 1.04=3.12m^2$

$Sectionfactor,Z_c=A_c\sqrt{\frac{A_c}{T}}$

=$3.12\sqrt{\frac{3.12}{3}}=3.18$